import java.util.Date;
import static java.lang.Math.*;
public class Main {

    public static void main(String[] args) {
        Student student1 = new Student("张三","男",10,"111");
        Student student2 = new Student("李四","男",11,"112");
        Student student3 = new Student("王五","男",12,"113");
    }

    public static void main5(String[] args) {
        double x = 30;
        double y = 40;
        //不静态导入的方式
        double result = Math.sqrt(Math.pow(x,2) + Math.pow(y,2));
        //静态导入的方式
        double ret = sqrt(pow(x,2) + pow(y,2));
        System.out.println(result);
        System.out.println(ret);
    }

    public static void main4(String[] args) {
        //util和sql中都存在一个Date这样的类，此时就会出现歧义，导致编译出错
        java.util.Date date = new java.util.Date();
        System.out.println(date.getTime());
    }

    public static void main3(String[] args) {
        Date date = new Date();
        //得到一个毫秒级别的时间戳
        System.out.println(date.getTime());
    }

    public static void main2(String[] args) {
        java.util.Date date = new java.util.Date();
        //得到一个毫秒级别的时间戳
        System.out.println(date.getTime());
    }

    public static void main1(String[] args) {
        Dog dog = new Dog();
        dog.name = "小黑";
        dog.age = 1;
        System.out.println(dog.name);
        System.out.println(dog.age);

        Dog dog2 = new Dog();
        dog2.name = "小黄";
        dog2.age = 10;
        System.out.println(dog2.name);
        System.out.println(dog2.age);
    }
}
